Laminated magnetic core structures for transformers or choke coils of great power



Sheet July 1,1969 A. H. TH. J. SLIEPENBEE LAMINATED MAGNE CORE STRUCTURES C B COILS OF GREAT FOR POWE Filed Jan. 19, 1968 w -x M u FIGJO ANToNius 9,

ATTO NEY;

y 1, 1969 A H. TH. J. SLIEPENBEEK 3,453,576

LAMlNATED MAGNETIC CORE STRUCTURES FOR TRANSFORMERS OR CHOKE CO'ILS OF GREAT POWER Filed Jan. l9, 1968 Sheet 3 of 2 INVENTOR ANToNius H 11 0. SLI'EPENBEEK ATTORNEYS United States Patent Int. Cl. H01f 27/24 US. Cl. 336-212 1 Claim ABSTRACT OF THE DISCLOSURE A laminated transformer coil having three legs joined at their opposite ends by carved coupling members and mutually inwardly directed equiangularly spaced yoke arms meeting at a common point. The inner ends of the yoke arms are provided with end edges including an angle of 120 and two yoke arms of each layer having unequal length end edges while the remaining one has equal length end edges, each end edge of the yoke arms in each layer being in abutting relation with one other end edge and the yoke arms of successive layers having the equal length end edges being oifset from the common point successively in dilterent directions along the axes of the yoke arms so as to avoid gaps between end edges while obtaining strip-like overlap at the end edges between successive layers.

The invention relates to a laminated magnetic core structure for a transformer or a choke coil of great power, comprising three leg members extending with their central longitudinal axes in the longitudinal edges of an equilateral prism, two star-shaped yoke members, each of which consists of three abutting yoke arms enclosing angles of 120 and having central longitudinal axes, which intersect in a common point, and coupling members, each of which connects an end of a leg member with the free end of a yoke arm, and in which core structure in at least a part of the total number of layers of laminations of the yoke members each yoke arm abuts at its end facing the two other yoke arms said other yoke arms with two end edges meeting in an angular point, whereas in each of said layers the common point of junction of said end edges of the yoke arms lies in oflset relation in the direction of the central longitudinal axis of one of the yoke arms with the common point of intersection of the central longitudinal axes of the yoke arms.

A magnetic core structure of this construction is disclosed in the French patent specification 1,229,933. Therein is the angle of the yoke ann enclosed by the end edges of the yoke arm, on the central longitudinal axis of which the common point of intersection of the abutting end edges of the three yoke arms lies, equal to 1'20-2u, whereas the angles enclosed by the end edges of the two other yoke arms are each equal to 120+u. The result of this construction is, that the laminations of the yoke arms of consecutive layers overlap each other with substantially triangular areas and the vertexes of said overlapping triangular areas lie at the outer edges of the yoke arms. This is unfavourable to obtain a strong mechanical connection between the yoke arms.

The invention has for its object to provide a magnetic core structure having similar yoke members, in which the connection between the yoke arms is considerably stronger. It consists in that in each of the said layers the angles of the yoke arms, which are enclosed by the end edges abutting each other, are all 120. In this case the joints of the yoke arm laminations of the different layers lie in offset relation and are parallel to each other, so that they are overlapped by strip-shaped areas of equal width. Consequently, the overlapping areas have at the outer edges of the yoke arms the same width as near the common point of intersection of said arms, which is favourable for the mechanical connection between the yoke arms.

The invention will be further elucidated with the aid of the drawing. Therein are:

FIG. 1 a view in perspective of a laminated magnetic core structure according to the invention,

FIGS. 2, 3, 4, 5, 6 and 7 on a larger scale plan views of six consecutive layers of laminations of a yoke member for a magnetic core structure shown in FIG. 1, and

FIGS. 8, 9 and 10 on a larger scale laminations for a yoke member composed of layers shown in FIGS. 2-7, when each of the laminations therefor has been divided along a line parallel to or coinciding with the central longitudinal axis.

In FIG. 1 of the drawing 1 are three vertical leg members extending with their longitudinal axes in the longitudinal edges of an equilateral prism, 2 are three horizontal yoke arms meeting with their central longitudinal axes in a common point of intersection 3 and enclosing angles of and 4 are circle-cylindrically curved coupling members extending between said leg members and said yoke arms of the magnetic core structure of a trans former or a choke coil of large power.

In the embodiment the leg members and the coupling members consist, in each layer, of two laminations of equal widths separated from one another by a cooling gap 5, however, the leg members and the coupling members may also consist in each one of the said layers of one single broad lamination.

In the embodiment shown in FIGS. 1-7 the yoke arms consist, in consecutive layers, either of a longer lamination 6 having two end edges 7, 8, which are equally long and enclose an angle of 120, and two laminations 9 having a longer end edge 10 and a shorter end edge 11, said end edges having unequal lengths but also enclosing an angle of 120 (FIG. '2), or of a shorter lamination 12 having two end edges 7, 8, which are equally long and enclose an angle of 120, and two laminations 9 (FIG. 3). In the layer shown in FIG. 2 the asymmetrical laminations 9 abut each other with their shorter end edges 11 and abut the end edges 7, 8 of the symmetrical lamination 6 with their longer end edges 10. On the other hand, in the layer shown in FIG. 3 the laminations 9 abut each other with their longer end edges 10 and they abut the end edges 7, 8 of the symmetrical lamination 12 with their shorter end edges 11. The layers shown in FIGS. 4 and 6 correspond with that shown in FIG. 2, however, with this exception, that each time the laminations 6 and 9 lie in other yoke arms. The same applies to the layers illustrated in FIGS. 5 and 7, which correspond to the layer shown in FIG. 3.

From FIG. 2 it appears that, when the layers shown in FIGS. 2-7 alternate with each other, the joints between the abutting laminations of the yoke arms lie in oifset relation and are parallel to each other, so that the laminations overlap one another with strip-like areas of equal width. Consequently, at the outer edges of the yoke arms the overlapping area has the same width as it has in the neighbourhood of the common point of intersection of said arms, which makes a strong mechanical connection between the yoke arms possible.

If the yoke arms are constructed in the manner shown in FIGS. '2-7, the laminations of a layer come to lie with their end edges remote from the common point of intersection in offset relation to the corresponding end edges of the laminations of adjacent layers (see the dotted lines in FIGS. 2-7). Consequently, the joints between the yoke arms and the coupling members come to lie in offset relation too, so that also the yoke arms and the coupling members intermesh with overlapping areas and thereby a strong mechanical connection is obtained.

FIGS. 2-7 show, that to form the yoke members of the magnetic core structure illustrated in FIG. 1 three different laminations are required. Two of these laminations, viz. the laminations 6 and 12, have a symmetrical shape and differ in length only, whereas the lamination 9 has an asymmetrical shape.

FIGS. 8, 9, 10 illustrate, that in each of the relevant layers of the yoke member each yoke arm may consist either of two laminations 15, 16 extending side by side and abutting with longitudinal edges 13, 14 parallel to the central longitudinal axis or of two equal laminations 19 and 20 extending side by side and abutting with the 15 longitudinal edges 17, 18, which coincide with the central longitudinal axis. In that case the lamination 15 has an oblique end edge 11, the lamination 16 an oblique end edge 10, the lamination 19 an oblique end edge 7 or 8 and the lamination 20 also an oblique end edge 7 or 8. The division of the laminations of the yoke arms has the advantage that the yoke arms can be made broader than the broadest available lamination and the laminations can be cut from strips of unlimited length without any loss of material. A yoke member of this construction can be composed of four diiferent laminations, that means of the laminations 15, 16, 19 and 20.

What I claim is:

1. A laminated magnetic core structure for a transformer or a choke coil of great power, comprising three leg members extending with their central longitudinal axes in the longitudinal edges of an equilateral prism, two star-shaped yoke members, each of which consists of three abutting yoke arms enclosing angles of 120 and having central longitudinal axes, which intersect in a common point, and coupling members, each of which connects an end of a leg member with the free end of a yoke arm, and in which core structure in at least a part of the total number of layers of laminations of the yoke members each yoke arm abuts at its end facing the two other yoke arms said other yoke arms with two end edges meeting in an angular point, whereas in each of said layers the coinmon point of junction of said end edges of the yoke arms lies in offset relation in the direction of the central longitudinal axis of one of the yoke arms from the common point of intersection of the central longitudinal axes of the yoke arms, with the direction of oifset being difierent in successive layers, characterized in that in each of the said layers the angles of the yoke arms, which are enclosed by the end edges abutting each other, are all References Cited UNITED STATES PATENTS 2,456,461 12/1948 Dunn 336-217 XR 2,579,578 12/ 1951 Horstman et a1. 336-217 XR 2,634,321 4/1953 Larkin 336-215 3,195,090 7/1965 Burkhardt et a1. 336-215 XR FOREIGN PATENTS 1,229,933 3/ 1960 France.

LEWIS H. MYERS, Primary Examiner.

T. J. KOZMA, Assistant Examiner.

U.S. Cl. X.R. 

